OneeChanbara (お姉チャンバラ?), initially defined The OneeChanbara (THE お姉チャンバラ?), is a series of action horror games developed by Tamsoft for D3 Publisher's Simple 2000 series for the PlayStation 2 and later ported on Xbox 360, Wii, PSP, PS3, PS4 and cellular phones. The title is a portmanteau of the Japanese words onee-chan (お姉ちゃん?, lit. "big sister", but also a colloquialism for a young adult woman) and chanbara (チャンバラ?, "sword fighting"). Commonly spelled and pronounced incorrectly as "Onechanbara" (as in [wuhn] instead of [O nē]), due to the simplified English/U.S. release titles, which has become a synonymous alternative spelling variation.
The hack and slash gameplay involves the player controlling Aya, a scantily-clad cowgirl who wears a scarf and wields a katana. The player is pitted against hordes of zombies and nightmarish boss creatures, who spill torrents of blood when they are attacked. Aya is often accompanied on her adventures by several other warrior women, such as her younger sister Saki, who appears in most titles in the series.